74 Osgood Thirty New Mice of the Genus Peromyscus. 



Measurements. Type (not quite adult): Total length, 241 ; tail vertebrae, 

 125; hind foot, 27. Ad. J 1 from Totontepec, Oaxaca: 262; 132; 30. 

 Skull of type: Greatest length, 31.6; basilar length of Hensel, 24.3; 

 zygomatic width, 15.2; nasals, 12; interorbital constriction, 5.4; pala 

 tine slits, 7.3; upper molar series, 5. 



Remarks. This mountain species is about the size of P. m. totontepecus, 

 with which it ranges to some extent, but is much more closely related 

 to megalops&nd auritus, as indicated by its cranial characters and its more 

 bristly tail. Its most diagnostic character, however, is the extent of 

 dusky brownish on the fore feet, which is almost unique. In some 

 specimens the ends of the toes and the outer side of the metacarpus are 

 the only parts not occupied by the dark color. The pelage is long and 

 lax like that of many other mountain forms. The type was taken at 

 8000 feet altitude. Five additional specimens from Totontepec on the 

 north slope of the same mountain at 6500 feet altitude are also in the col 

 lection. P. lepturus, which also occurs on Mt. Zempoaltepec, is smaller 

 than melanocarpus and differs in numerous cranial characters, among the 

 most obvious of which are : Braincase smaller and narrower, interorbital 

 constriction narrower, nasals shorter, supraorbital beads less developed. 





 Peromyscus altilaneus sp. nov. 



Type from Todos Santos, Guatemala (altitude 10,000 feet). Adult male, 

 No. 76,856, U. S. National Museum, Biological Survey Collection, Decem 

 ber 30, 1895, E. W. Nelson and E. A. Goldman. 



Characters. Similar to P. melanocarpus, but smaller and with shorter and 

 less hairy tail ; fore feet entirely white ; hind feet with much more white 

 than in melanocarpus; skull slightly smaller and more slender ; similar to 

 guatemalensis but much smaller. 



Color. As in melanocarpus, but tail blotched with yellowish white 

 below, much as in mexicanus : fore feet and part of forearm white; hind 

 foot with a V-shaped dusky mark extending from ankle about half way 

 to the base of the toes, remainder of foot white ; pectoral spot strongly 

 developed in type. 



Skull. Similar to that of melanocarpus, but slightly smaller throughout ; 

 nasals relatively more expanded anteriorly ; braincase slightly higher and 

 more inflated and rostral region more depressed ; anterior palatine foram 

 ina shorter; infraorbital plate very narrow. 



Measurements. Type: Total length, 228; tail vertebrae, 115; hind foot, 

 28. Skull: Greatest length, 31; basilar length of Hensel, 24; zygomatic 

 width, 14.6; interorbital constriction, 5; nasals, 11.5; bony palate, 4.8; 

 palatine slits, 6 x 2.7 ; diastema, 8.2; postpalatal length, 11.2; upper 

 molar series, 4.6. 



Remarks. The type of this species is the only specimen known at pres 

 ent. Its only close relationship is with P. melanocarpus, to which it is 

 very similar except in regard to the color of the wrists and fore feet. 

 From P. lepturus it differs in darker color, strongly developed pectoral 



